Vegans, Vegetarians and Pescatarians Are at Risk of Iodine Deficiency in Norway.

Synne Groufh-Jacobsen,Kristina Blandhoel Pettersen,Inger Aakre,Elin Lovise Folven Gjengedal,Sigrun Henjum,Sonja Y Hess

doi:10.3390/nu12113555

Abstract

Low iodine intakes have been documented in different population groups in Norway. We aimed to assess iodine status, dietary intake, supplement and macroalgae use, and iodine knowledge in vegans, vegetarians and pescatarians. In this study, 115 vegans, 55 vegetarians and 35 pescatarians from the Oslo region of Norway, aged 18–60 years, participated. A spot urine sample was collected along with a dietary assessment of iodine intake, supplement and macroalgae use. The median urinary iodine concentration (MUIC) in vegans was 43 µg/L (moderate iodine deficiency), in vegetarians 67 µg/L and in pescatarians 96 µg/L (mild iodine deficiency). In multiple linear regression analysis, use of iodine supplements was one of the strongest predictors of UIC. About half of the participants had median 24-h iodine intakes below estimated average requirement (EAR) of 100 µg/day. Fifty percent had low knowledge score, while 27% had very low knowledge score. Vegans, vegetarians and possibly pescatarians in Norway, are unable to reach the recommended iodine intake merely from food and are dependent on iodine supplements. There is an urgent need for dietary guidance targeting vegans, vegetarians and pescatarians to avoid inadequate iodine intake in non-supplement users, as well as avoiding excess iodine intake in macroalgae users.

Highlights

Plant-based diets, especially veganism, are increasing all over the world [1]
Changing from an omnivorous to a vegetarian or vegan dietary practice has been associated with several health benefits including a reduced risk of coronary heart disease [5], these diets may be associated with an increased risk of micronutrient deficiencies [6,7]
Urinary iodine concentration μg/L was LOG 10- transformed; Vegan dietary practice (0 = vegetarian and pescatarians, 1 = vegans); 3 Iodine supplement use (0 = no, 1 = yes); 4 Higher education (0 = less than 12 years education, 1 = more than12 years education); 5 Confidence interval; 6 Adjusted for vegan dietary practice, 24-h iodine supplement use; higher education; Independent variables that were not significant or further increasing the explained variance were not included in this final model. This is the first study in Norway to investigate iodine status, dietary iodine intake, supplement use, macroalgae consumption and iodine knowledge in a relatively large sample of vegans, vegetarians and pescatarians

Summary

Introduction

Plant-based diets, especially veganism, are increasing all over the world [1]. In Norway, 2–4% reported to be adhering to a vegan or vegetarian dietary practice in 2004 [2], today the number has most likely increased further. In Sweden the number of vegans and vegetarians increased from 3 to 10% between 2007 and 2014 [4]. Changing from an omnivorous to a vegetarian or vegan dietary practice has been associated with several health benefits including a reduced risk of coronary heart disease [5], these diets may be associated with an increased risk of micronutrient deficiencies [6,7]. Vegans consume plant-based foods and omit all types of animal-products. People adhering to a vegetarian, pescatarian or vegan diet may risk nutritional

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